It is known to use nonwoven fiber, such as glass fiber, mats bonded with a thermosetting resin, like urea formaldehyde, to laminate to polymeric foam such as polystyrene foam to act as stiffeners and stabilizers in the manufacture of automotive parts such as automobile head liners as disclosed in U.S. Pat. No. 4,729,917. Products produced with foam laminates having one or two layers of nonwoven fiber glass mat with urea formaldehyde binder are affected by high humidity and high ambient temperature to cause an unpleasant odor and also to deteriorate the binder strength. Also, non-extendible mat, i.e. a mat bound with a resin binder that is fully cured is relatively stiff and does not conform well to curves and complex curvature, such as three dimensional curvature, and still provide excellent rigidity or stiffness to the foam laminate.
It is also known to make nonwoven fiber glass mats for bonding to a layer of polymeric foam to stiffen the foam by chopping dry strands of glass fibers bound together with a binder to form chopped strand, to collect the chopped strand on a moving conveyor in a random pattern, and to bond the chopped strand together at their crossings by dusting a dry, powdered thermoplastic binder like a polyamide, polyester or ethylene vinyl acetate on wetted chopped strands followed by drying and curing the binder, as disclosed in U.S. Pat. No. 5,565,049. While such products may work, the mat does not have as high a tensile strength as desired and as achieved with a wet laid nonwoven fiber glass mat because the bundles or chopped strands in the mat, according to the disclosure of the above cited patent, do not bond together as well as the individual fibers in a typical nonwoven mat. For example, the average sum of the machine direction tensile and the cross machine direction tensile for a chopped fiber glass strand mat made in this manner and having a basis weight of about 1.88 pounds per 100 sq. ft. is about 24 lbs. per 3 inch width compared to at least twice this tensile for wet laid nonwoven fiber glass mats. Mats made according to the process of U.S. Pat. No. 5,565,049 also are more expensive to make than a typical nonwoven mat made with known wet laid processes.
It is also known to use an acrylic copolymer latex, such as a self-crosslinking acrylic copolymer of an anionic emulsifying type as one component of at least a two component binder for bonding glass fibers and particulate thermoplastic to make a glass fiber reinforced sheet that can later be hot molded into various shapes and articles, as disclosed in U.S. Pat. No. 5,393,379. The sheet products taught by this patent would not be suitable to use for stiffening foam layers because of the presence of the substantial amount of particulate thermoplastic in the sheet.